Canon RF 600mm f/11 IS STM The Diminutive Giant

The Canon RF 600mm f/11 IS STM is retractable and small, portable and light, and surprisingly inexpensive for its focal length.K Madhavan Pillai discovers more.

- K Madhavan Pillai

Canon is certainly sweetening the deal for RF-mount camera owners and prospective buyers. Announced in July 2020, the RF 600mm and RF 800mm (both with no aperture diaphragms within the lenses, with aperture values fixed at f/11) was intriguing, to say the least. There are some big benefits in having a fixed focal length and aperture. Optics can be simplified and designed for performance. Blurs and bokeh is optimised by the perfectly circular aperture. The lens can be made smaller, lighter and designed to be portable.

Features

Contributing to the reduced size is a collapsible or retractable barrel-in-barrel design, along with a distinct but simplified optical layout that Canon has been perfecting for decades. The Canon RF 600mm f/11 IS STM uses gapless dual-layer diffractive optics instead of multiple heavier individual elements, which also controls fringing, aberrations, and flare. An STM stepping motor delivers quick, quiet AF, suitable for both stills and video. It also allowing full compatibility with the RF 1.4x and 2x extenders, for an effective focal length of 840mm or 1200mm, respectively. There is an AF range limiter switch that locks out the closer focusing range between 4.5m (or 14.75 feet, a modest closest focus distance) and 12m, to speed up subject acquisition at longer distances.